1. Field of the Invention
The present invention relates to an optical pickup and an optical disk apparatus that can perform recording or playback of three types of disks, namely, a CD (compact disk), a DVD (digital versatile disk), and a next-generation optical disk such as a Blu-ray Disc (hereinafter abbreviated as a “BD”) which is a registered trademark). More particularly, the present invention relates to the arrangement of a CD/DVD objective lens and a BD objective lens.
2. Description of the Related Art
In recent years, CDs and DVDs on and from which image information and music information are recorded and played back have become widespread. In order to satisfy a demand to further increase the recording density and capacity, next-generation optical disks, for example, Blu-ray Discs that use laser light having a wavelength of 407 nm in the blue wavelength region, have been introduced.
Correspondingly, optical disk apparatuses that perform recording and playback of these disks have been developed and commercialized. The optical disk-apparatuses include two optical pickups, that is, an optical pickup for both CDs and DVDs and an optical pickup only for BDs, or a single optical pickup that can perform recording and/or playback of CDs, DVDs, and BDs. From the viewpoint of space, it is extremely natural to mount a single optical pickup that can perform recording and/or playback of CDs, DVDs, and BDs. Such an optical pickup is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2003-323735.
When recording or playback of CDs, DVDs, and BDs are performed with a single optical pickup, it is necessary to reduce the size and weight of the pickup and to respond to the increase of recording speed. Correspondingly, an objective lens for both CDs and DVDs and an objective lens only for BDs need to be arranged to apply laser light onto an optical disk and to receive reflected light from the optical disk.